In the field of graphic arts, graphic artists create and combine text and images from various applications such as the Adobe Photoshop®, Adobe Illustrator®, and Adobe InDesign® computer programs (all available from Adobe Systems Incorporated, of San Jose, Calif.) to create professional graphic documents. For example, images may be created in Adobe Photoshop®, while line art may be created in Adobe Illustrator®, and the entire page layout may be synthesized in Adobe InDesign®. Ultimately, a finished graphic document may be printed on a specifications for web offset publications (SWOP) press or other cyan, magenta, yellow, and black (CMYK) based output device.
During the process of creating a graphic document, elements such as images, fills, line art, and text may move from one application to another until they take their final form and the entire document is sent to a printer. The steps a document goes through, from the creation and merging of its component elements to its final editing and printing, using different applications and display devices along the way, is termed its workflow. Most modern graphics applications include color management routines that perform some degree of color management, or manipulation of the colors of objects within a document, as the document is imported into, and exported out of, the applications.
Color management routines are designed to reconcile the different color capabilities of the various scanners, monitors, cameras, and printers that may create or handle an object or a document as the object or document travels along its workflow. Typically, color management routines include routines to read and write device profiles, and to render colors from a source color space associated with a source device to a destination color space associated with a destination device. Device profiles define the color characteristics of the source and destination devices, and are used by the color management routines to map object colors from the source color space to the destination color space through an intermediate, device independent, color space. Depending on the color gamuts of the source and destination devices, not all of the colors available in the source color space may be available in the destination color space. Colors that are available in the source color space but unavailable in the destination color space are mapped to an appropriate destination color available in the destination color space by the color management routines.
As a result of color management, particularly as a result of mapping out-of-gamut colors in the destination color space to their nearest in-gamut colors, colors associated with objects in a document may undergo subtle changes as the document moves along its workflow. While color management induced color changes are useful for many objects in a document, it is important that some objects retain their color throughout a document's workflow. For example, a black or neutral gray text object incorporated into a document as a label ought to retain its neutral color throughout the document's workflow. By retaining its color, such an object will be printed using only a printer's black ink, and will therefore appear in print to have a neutral black or gray color as intended.
Currently, the colors of all objects in a document are color managed or manipulated throughout the document's workflow by the color management routines of each application handling the document. As a result, text objects created with neutral grays and blacks may lose their “grayness” over the course of the workflow, and be printed with non-neutral colors. For example, a black text object created in an RGB color space in one application may be transformed to an HSB color space in another application and back to an RGB color space of a third application as the document containing the text object moves along its workflow. If as a result of color management, or color transformation errors, the final text object's red, green, and blue color-tuple components are not identical, the object will not be printed with the printer's black ink alone, but will be printed with an admixture of the printer's cyan, yellow, or magenta inks. Thus, the object will lose its intended neutral gray color in print.